a b s t r a c t

Introduction: The literature indicates that youth with intellectual/developmental disabilities (IDD) have poor health and that access to health services decreases as they transition from pediatric to adult services. At the same time their use of emergency department services increases. The objective of this study was to compare use of emergency department services by youth with IDD to youth without IDD, with particular emphasis on the transition period from pediatric to adult health care services.

Methods: This research used a population level administrative health data base for the province of British Colum- bia Canada for 2010-2019 to examine the use of emergency departments by youth with IDD (N = 20,591) com- pared to a population group of youth without IDD (N = 1,293,791). Using the ten years of data, odds ratios for visits to the emergency department were calculated adjusting for sex, income and Geographical area within the Province. In addition, difference-in-differences analyses were calculated for age matched subsets of the two cohorts.

Results: Over the ten year period, 40.60% of youth with IDD visited an emergency department at least once, com- pared to 29.10% of youth without IDD. Youth with IDD had an odds ratio of visiting an emergency department 1.697 (1.649, 1.747) times that of youth without IDD. However, when odds were adjusted for a diagnosis of either psychotic illness or anxiety/depression, the odds for youth with IDD visiting emergency compared to youth with- out IDD were reduced to 1.063 (1.031, 1.096). Use of emergency services increased as youth aged. Type of IDD also affected use of emergency services. Youth with Fetal Alcohol Syndrome had the greatest odds of using emer- gency services compared to youth with other types of IDD.

Discussion: The findings from this study indicate that youth with IDD have higher odds of using emergency ser- vices than youth without IDD although these increased odds appear to be largely driven by Mental illness. In ad- dition, use of emergency services increases as the youth age and transition from pediatric to adult health services. Better treatment of mental health issues within this population may reduce their use of emergency services.

(C) 2023

1. Introduction

There is considerable evidence that people with intellectual/devel- opmental disabilities (IDD) experience poorer health and Health care disparities compared to non-disabled people [1-3]. This poorer health is seen in adolescents with IDD compared to adolescents without IDD [4,5]. Also, among people with IDD, there is evidence that the transition from child to adult is associated with a decline in health [6,7].

* Corresponding author.

E-mail addresses: [email protected] (S. Marquis), [email protected] (Y. Lunsky), [email protected] (K.M. McGrail), [email protected] (J. Baumbusch).

For people with IDD, a decrease in health during the transition to adulthood may be associated with a decline in access to health care ser- vices [8]. Nathenson and Zablotsky [9] found a decline in the use of health care services, except for emergency services, by autistic youth transitioning to adult services. Hamdani and Lunsky [10] also found that as youth aged there was a shift from the use of community and outpatient care in childhood toward the use of more hospital-based, emergency, and long-term care in adulthood.

There is evidence that youth with IDD use emergency services more frequently than youth without IDD [11]. Liu et al. [12] found that autistic adolescents accessed emergency department services four times as often as non-autistic adolescents. Weiss et al. [13] reported that youth

https://doi.org/10.1016/j.ajem.2023.04.006

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with ASD had greater odds of visiting an emergency department com- pared to youth with no developmental disability. Liu et al. [14] found that higher use of emergency department services by autistic adoles- cents was related to co-existing intellectual disability, being female, in- creasing age, living in a rural area, visiting a primary care physician or psychiatrist in the past six months, psychiatric co-morbidities and use of Psychotropic medications.

However, overall there is limited information regarding emergency services use by youth with IDD and studies of people with IDD often have small sample sizes, rely on convenience sampling and do not have an appropriate comparison group [15]. This study addressed the lack of population level data on use of emergency services by youth with IDD by using population-level administrative health data for the entire province of British Columbia and comparing youth with IDD to a large population group of youth without IDD. The goal of this study was to compare use of emergency services between youth with IDD and youth without IDD, especially during their transition from pediatric care to adult health care services.

1. Methods

This research used a retrospective Cohort study design. The study population was youth aged 15 to 24 years old diagnosed with an intel- lectual/developmental disability. The comparison cohort was all other youth aged 15-24 in British Columbia (BC). The time frame used was 2010-2019. Population-level administrative health data was obtained from the British Columbia Ministry of Health via Population Data British Columbia. Population Data BC provides linkages of administrative data and access to data extracts to researchers [16]. For this study four data sets were linked using individual unique and study specific codes that provide anonymity. The four data sets were: a central consolidation file [17] with demographic information on all individuals in British Co- lumbia, the Medical Services Plan (MSP) payment files that contain in- formation for all fee-for-service care provided by physicians in B.C.

[18]; the hospital separation file that contains information on all hospi- talizations in B.C. [19] and data from the National Ambulatory Care Reporting System [20]. The B.C. Ministry of Health provided approval for data access and the University of British Columbia provided ethics approval (#H20-03028).

Youth with IDD were identified using ICD-9 and ICD-10 codes as de- scribed in the algorithm developed by Lin et al. [21] (see Appendix A for a list of Diagnostic codes). To ensure the identification of as many youth with IDD as possible, medical records were examined from 1986 to 2019 and individuals with IDD traced forward and backward in time. The diagnosis with an IDD was either a primary diagnosis or a secondary diagnosis noted by physicians when submitting billing requests or re- corded in hospitalization data. Type of IDD was further subdivided into youth with Fetal Alcohol Syndrome (FAS), autism, Down syndrome or ‘other’. Other consisted of youth with any other IDD not included in the first three groups. In addition, youth with more than one type of IDD diagnosis (i.e. autism plus Down syndrome or FAS plus autism) were grouped together as a separate variable and compared to youth with a single type of IDD diagnosis.

Visits to the emergency department were recorded in the adminis- trative data. Additional health services variables included whether or not the person had a diagnosis of anxiety/depression or a diagnosis of a psychotic illness. Diagnoses of anxiety/depression and psychotic dis- orders were identified using ICD-9 and ICD-10 codes in Medical Services Plan and hospital data (see Appendix A for a list of diagnostic codes).

Using the overall group, and ten years of data, all youth with IDD were compared to all youth without IDD. To examine the transition of youth from pediatric to adult health care services, a transition subset of the larger group with IDD and the larger group without IDD were formed. This transition subset included all youth aged 15 years in 2010, 16 years in 2011, 17 years in 2012 etc., to 24 years in 2019. Only

youth with data in each of the 10 years were included in the transition subset.

Descriptive statistics were reported for the large group of youth with IDD and the comparison group; variables included sex, receipt of a Med- ical Services Plan (MSP) subsidy, neighbourhood income quintile and the geographic health authority area in which the youth lived. MSP sub- sidy was used as an indication of poverty. In B.C., prior to 2020, MSP pre- miums were paid by individuals or employer plans. low income people received a provincial subsidy to cover their MSP costs.

The overall ten year use of emergency services was reported for youth with IDD and youth without IDD. Chi-square tests and t-tests were used to compare proportions and means between the two study groups. Multiple logistic regression analyses were used to calculate odds ratios and 95% confidence intervals for having a visit to the emer- gency department vs not having a visit to the emergency department. Initially the logistic regression analyses were adjusted for sex, income and geographic area. Subsequently data analyses were adjusted for a diagnosis of anxiety/depression or a diagnosis of a psychotic disorder.

In addition, difference-in-differences statistics were conducted to compare the mean use of emergency services over time as the youth transitioned from pediatric health services to adult services at age 19. Difference in differences methods compare changes over time in an out- come between exposed and comparison groups using repeated mea- sures Generalized linear models [22,23]. The analyses compare the population averages between two time periods for the exposed and comparison groups. All programming and data analyses was conducted using SAS version 9.4 [24].

1. Results

Descriptive statistics can be found in Table 1. Using all 10 years of data, a total of 20,591 youth with IDD and 1,293,791 youth without IDD were identified in the linked data. In this sample youth with IDD were 1.57% of the population of youth aged 15-19 in B.C. in the years 2010-2019. The cohort with IDD had a higher number of males com- pared to females than was found in the comparison group. At any time in the ten years, 35% of the IDD group received an MSP subsidy compared to 18% of the comparison cohort. There were also a greater number of people with IDD in the neighbourhoods with the lowest in- come quintile compared to the comparison group. In the whole group of youth with IDD, over the ten year period, 40.60% of youth visited an emergency department compared to 29.10% of youth without an IDD. Significantly more youth with IDD were diagnosed with either a psy- chotic illness or anxiety/depression compared to youth without IDD.

After adjusting for sex, neighbourhood income quintile, receipt of an MSP subsidy and Health Authority area, analyses comparing the large group of youth with IDD and the group without IDD (Table 2), found that youth with IDD had greater odds (1.697 (1.649, 1.746)) of using emergency services. However, when the variable of whether or not the youth had a diagnosis of anxiety/depression or a psychotic illness was added, youth with IDD had only slightly greater odds (1.063 (1.031, 1.096)) than youth without IDD (Table 2). Among all youth, odds of a youth with a diagnosed psychotic illness or a diagnosis of anx- iety/depression visiting the emergency department were greater than youth without these diagnoses when presence or absence of an IDD was held constant (Table 2).

When analyses were done for the transition subset of youth who were 15 years old in 2010 and progressed to being 24 in 2019, the odds of visiting the emergency department were considerably greater for youth with IDD compared to youth without IDD. Again these odds were reduced if having a diagnosis of anxiety/depression or a psychotic illness were included as variables in the analyses (Table 3).

Difference in differences analyses compared the average number of visits to the emergency department in youth aged 15-19 to youth aged 20-24 and between youth with IDD and youth without IDD. Re- sults showed that there was a significant increase in the average

Descriptive Statistics for Youth With and Without IDD in British Columbia 2010-2019.

Variable	Youth with IDD	Youth without IDD
Total number of people	20,591	1,293,791
Male (%)	14,138 (68.66%)	656,159 (50.72%)
Female (%)	6452 (31.33%)**	637,627 (49.28%)**
Receiving an MSP subsidy (%) (receiving a subsidy at any point of time within	7207 (35.00%)**	231,674 (17.91%)**
2010-2019) Neighbourhood Income Quintile (measured at the last time the person is identified in the data)
1st (lowest)	4666 (22.76%)	250,276 (19.58%)
2nd	4157 (20.28%)	253,980 (19.87%)
3rd	3893 (18.99%)	258,905 (20.26%)
4th	3984 (19.43%)	245,465 (19.21%)
5th (highest)	3615 (17.63%)	246,276 (19.27%)
Type of IDD (number and % of persons with an IDD)
Autism	11,305 (54.90%)
Down syndrome	967 (4.70%)
FAS	1955 (9.49%)
Other	6364 (30.91%)
Multiple diagnoses (people with 2 or more types of IDD diagnoses	3549 (17.24%)

(i.e. Down syndrome + autism etc.))

Total number and percent of youth who visited an emergency department 8360 (40.60%)** 376,493 (29.10%)**

Ten most common emergency department diagnoses (in descending order) 1. Symptoms and signs involving emotional state

• 1. Unspecified mental disorder
  2. Acute and transient psychotic episode
  3. Depressive episode
  4. Unspecified abdominal pain
  5. Unspecified convulsions
  6. Mental and behavioural disorders due to multiple drug use
  7. Unknown and unspecified causes of morbidity
  8. Schizophrenia, unspecified
  9. Chest pain, unspecified

1. Unspecified abdominal pain
2. Symptoms and signs involving emotional state
3. Depressive episode
4. Acute appendicitis
5. Chest pain, unspecified
6. Concussion
7. Unknown and unspecified causes of morbidity
8. Strain and sprain of ankle
9. Anxiety disorder, unspecified
10. Urinary tract infection

Total number and percent of people with at least one diagnosis of a psychotic illness

Total number and percent of people with at least one diagnosis of anxiety/depression

?? p < 0.001.

4118 (20.00%)** 48,109 (3.72%)**

10,021 (48.67%)** 289,278 (22.36%)**

number of visits to the emergency department for both youth with and without IDD as they aged. The increase was greater for youth without IDD than for youth with IDD; however, the average number of visits for youth with IDD remained greater than the average number of visits for youth without IDD (Table 4).

Within the group of youth with IDD, 31.32% of youth with Down syndrome visited an emergency department compared to 36.79% of youth with autism, 42.87% of youth with ‘other’ and 58.86% of youth

with FAS. Youth with more than one type of IDD diagnosis were more likely to visit an emergency department compared to youth with a sin- gle type of IDD diagnosis (46.24% compared to 39.43%). Data also varied by sex; 45.16% of female youth with IDD visited an emergency depart- ment compared to 38.52% of males with IDD.

Logistic regression analyses (Table 5) found that when type of IDD, health authority area and neighbourhood income quintile were held constant, females with IDD had higher odds of using emergency room

Table 2

Odds of Emergency Department Use by the Total Population of Youth with IDD Compared to the Total Population of Youth Without IDD.

Variables Odds of a visit to an emergency

department adjusted for sex, income, and Health Authority (N = 20,591)

Odds of a visit to an emergency department adjusted for sex, income, Health Authority and a diagnosis of a mental health issue (psychotic illness or anxiety/depression) (N = 1,293,791)

Cohort

Youth with IDD vs youth without IDD 1.697 (1.649, 1.746) 1.063 (1.031, 1.096) Sex

Female vs male	1.025 (1.018, 1.033)	0.886 (0.879, 0.893)
Receipt of an MSP Subsidy vs no Subsidy	1.338 (1.326, 1.349)	1.167 (1.157, 1.177)
Health Authority Interior vs Vancouver Coastal	0.724 (0.715, 0.734)	0.623 (0.614, 0.632)
Fraser vs Vancouver Coastal	1.199 (1.187, 1.210)	1.145 (1.133, 1.156)
Vancouver Island vs Vancouver Coastal	1.367 (1.350, 1.384)	1.218 (1.202, 1.233)
Northern vs Vancouver Coastal	0.624 (0.612, 0.636)	0.543 (0.532, 0.554)
Diagnosis of a psychotic illness vs no diagnosis of a psychotic illness		2.695 (2.640, 2.750)
Diagnosis of anxiety/depression vs no diagnosis of anxiety/depression		3.202 (3.172, 3.232)

Table 3

Number of Youth Visiting Emergency Departments 2010-2019 and Odds Ratios.

Year and age	Youth with IDD (number and percent of people with one or more visits to emergency services)	Youth without IDD (number and percent of people with one or more visits to emergency services)	Odds ratio (95% CI) (odds of having a visit to emergency services, youth with IDD compared to youth without IDD; adjusted for sex, income and Health Authority)	Odds ratio (95% CI) (odds of having a visit to emergency services, youth with IDD compared to youth without IDD adjusted for sex, income, Health Authority and a diagnosis of anxiety/depression or a diagnosis of a psychotic illness)
2010	32 (3.22%)	322 (0.72%)	4.112 (2.815, 6.006)	1.995 (1.314, 3.028)
15 years old 2011	52 (5.24%)	643 (1.43%)	3.329 (2.479, 4.471)	1.867 (1.345, 2.592)
16 years old 2012	73 (7.35%)	749 (1.66%)	4.696 (3.637, 6.063)	2.247 (1.687, 2.991)
17 years old 2013	59 (5.94%)	842 (1.87%)	2.977 (2.246, 3.947)	1.521 (1.113, 2.078)
18 years old 2014	66 (6.65%)	823 (1.83%)	3.314 (2.551, 4.306)	1.374 (1.007, 1.875)
19 years old 2015	60 (6.04%)	828 (1.84%)	3.427 (2.605, 4.509)	1.491 (1.086, 2.045)
20 years old 2016	81 (8.16%)	841 (1.87%)	4.665 (3.663, 5.941)	2.324 (1.755, 3.077)
21 years old 2017	71 (7.15%)	851 (1.89%)	4.078 (3.168, 5.250)	1.930 (1.447, 2.576)
22 years old 2018	60 (6.04%)	828 (1.84%)	3.427 (2.605, 4509)	2.174 (1.629, 2.901)
23 years old 2019	52 (5.24%)	643 (1.43%)	3.748 (2.798, 5.020)	1.738 (1.246, 2.426)
24 years old

Table 4 Difference in Differences Analyses for Visits to the Emergency Department 2010-2019.
	Youth with IDD	Youth without IDD	Significance
Mean number of visits in youth aged 15-19 in the five year period (2010-2014)	4.47	0.05	p < 0.0001
Mean number of visits in youth aged 20-24 in the five year period (2015-2019)	5.86	2.33	p < 0.0001
Difference in mean number of visits between time periods Effect of time	1.39	2.28	p < 0.0001
Effect of time x cohort			p < 0.0001

services compared to males with IDD. Adjusting for other variables, youth living in the Northern Health Authority had fewer visits to the emergency department compared to youth in the large primarily urban Health Authority of Vancouver Coastal. When sex, health author- ity and income were held constant, youth with Fetal Alcohol Syndrome, autism and ‘Other’ all had greater odds of visiting the emergency de- partment compared to youth with Down syndrome. Youth with more

than one type of IDD diagnosis had greater odds of an emergency room visit compared to youth with a single diagnosis IDD type.

When mental health diagnoses were included in the logistic regres- sion analyses there was no significant differences between Males and females and the odds of visiting an emergency department were re- duced for youth with FAS, autism and ‘Other’. The odds of visiting an emergency room were greater for youth with a psychotic illness

Table 5

Odds of Emergency Department Visits Within the Total Population of Youth with IDD.

Variables Odds of a visit to an emergency

department adjusted for sex, income, type of IDD and Health Authority

Odds of a visit to an emergency department adjusted for sex, income, type of IDD, Health Authority and a diagnosis of a mental health issue (psychotic illness or anxiety/depression)

Sex

Female vs male 1.259 (1.182, 1.341) 1.084 (1.014, 1.160)

Receipt of an MSP Subsidy vs no Subsidy 0.629 (0.587, 0.673) 0.638 (0.592, 0.688) Type of IDD

FAS vs Down syndrome 3.533 (2.978, 4.190) 1.849 (1.544, 2.215)

Autism vs Down syndrome 1.358 (1.166, 1.583) 0.750 (0.640, 0.880)

Other vs Down syndrome 1.628 (1.403, 1.890) p < 0.0001 1.077 (0.922, 1.258)

Health Authority

Interior vs Vancouver Coastal	0.439 (0.399, 0.483)	0.397 (0.358, 0.439)
Fraser vs Vancouver Coastal	0.936 (0.863, 1.016)	0.922 (0.845, 1.005)
Vancouver Island vs Vancouver Coastal	0.953 (0.870, 1.044)	0.926 (0.841, 1.020)
Northern vs Vancouver Coastal	0.435 (0.612, 0.636)	0.405 (0.353, 0.465)
Multiple IDD diagnoses vs a single IDD diagnosis	1.129 (1.035, 1.232)	0.855 (0.779, 0.939)
Diagnosis of a psychotic illness vs no diagnosis of a psychotic illness		2.808 (2.586, 3.049)
Diagnosis of anxiety/depression vs no diagnosis of anxiety/depression		2.729 (2.556, 2.914)

diagnosis or an anxiety/depression diagnosis compared to youth who did not have these comorbid diagnoses (Table 5).

1. Discussion

In this study use of emergency department services by youth with IDD was measured using the number of youth visiting an emergency de- partment over a ten year period and the number of youth in a transition subset of the cohort who visited an emergency department over time. The average number of visits to an emergency department was also ex- amined for youth aged 15-19 and compared to youth aged 20-24.

The literature indicates that youth with IDD use emergency depart- ments to a greater extent than youth without an IDD. The population- level data used in this study supports these previous findings. The data in this study also indicates that the use of emergency department services increases for all youth as they become young adults.

In the total population, emergency departments have seen an in- crease in the number of visits due to mental health issues for both pedi- atric [25] and youth populations [26]. Kalb et al. [26] described emergency departments as the “national safety net for individuals with chronic and acute mental health issues”. Lin et al. [27] found that people with IDD were at greater risk of using emergency departments if they also had a mental health diagnosis. This finding is corroborated in the current study. Analyses in this study demonstrate that mental health diagnoses influence the odds of visiting the emergency depart- ment. When odds ratios are adjusted for mental health diagnoses, the odds of visiting the emergency department are reduced for youth with IDD. At the same time, British Columbia and Canada are experiencing a shortage of mental health workers and an increase in demand for mental health services [28,29]. Within this climate, these results indi- cate not only the need for mental health services for youth but also the need for better planning to connect youth with mental health ser- vices following discharge from emergency departments.

Even after adjusting for mental health diagnoses, the odds of youth with IDD visiting an emergency department were greater than youth without IDD. In addition, in this study holding other variables constant, females had greater odds of a visit to the emergency department compared to males; however when mental health diagnoses were added as variables to the logistic regression, females had significantly lower odds of a visit to the emergency department compared to males. This finding is supported by data indicating that females visit the emergency department for mental health issues to a greater extent than do males [25].

The findings in this study also indicate that youth with different types of IDD diagnoses use emergency services to varying degrees. In the past, most studies of emergency use have been of youth or adults with autism [30]. This study is unique; emergency visits were compared between four types of IDD. This study found that youth with Fetal Alco- hol Syndrome have particularly high odds of using emergency depart- ment services. This result may be due to the high prevalence of mental health issues in this population [31].

This study used population-level administrative health data which ensures that a relatively large number of an otherwise small population of people can be obtained and that the results can be generalized to the overall population of youth with IDD. The data also allows examination of a variety of IDD types, analysis of the effect of time, use of a population-level comparison group, and ensures anonymity.

However, administrative data used for billing purposes does not in- clude information regarding potentially important variables including ethnicity or race and severity of disability. There is indication for exam- ple that people with mild IDD use the emergency department to a greater extent than those with moderate or severe IDD [32]. The vari- able of sex in the administrative data only supplies the variable fe- male/male; there is no information available on gender. In addition, measures of income used in this study are not precise. Other variables such as accessibility to primary health care, life events, type of housing

and type of support may also be important variables for consideration [32]. The perspective of people with IDD and their experiences are also not included in this study but are an important component of assessing health care services use.

Over and under-estimation of effects are possible limitations of the study. Odds ratios in logistic regression are affected by sample size [33]. This effect may be seen in the data for the whole population com- pared to the data for the age matched groups. The age matched groups have smaller sample sizes and greater odds ratios.

In conclusion, the findings in this study indicate that youth with IDD use emergency services to a greater degree than youth without IDD. In addition, the findings illustrate the interaction between mental health issues and use of emergency services for these youth. Improved treat- ment of mental health issues within this population could reduce their use of emergency services.

Funding sources

Sandra Marquis was funded for this study by Michael Smith Health Research British Columbia (RT-2020-0516).

Disclaimer

Access to data provided by the Data Steward(s) is subject to approval, but can be requested for research projects through the Data Steward

(s) or their designated service providers. All inferences, opinions, and conclusions drawn in this publication are those of the author(s), and do not reflect the opinions or policies of the Data Steward(s).

CRediT authorship contribution statement

Sandra Marquis: Writing - review & editing, Writing - original draft, Methodology, Investigation, Funding acquisition, Formal analysis, Data curation, Conceptualization. Yona Lunsky: Writing - review & editing, Supervision, Methodology, Funding acquisition. Kimberlyn M. McGrail: Writing - review & editing, Methodology, Funding acquisition. Jennifer Baumbusch: Writing - review & editing, Supervision, Re- sources, Project administration, Funding acquisition, Conceptualization.

Conflicts of interest

The authors have no conflicts of interest to declare.

Acknowledgements

N. Esme Marquis MD CCFP.

Appendix A. Supplementary data

Supplementary data to this article can be found online at https://doi. org/10.1016/j.ajem.2023.04.006.

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